Improvement in compound steam-engines



A. ALEXANDER. Compound Steam-Engine.

No. 163,348 Patented Mag 18,1875.

.7 V W a l KN PHUI\E I.

WITPJESEES v M dim/1w 41444 4401211 M fi' fizz THE GRAPHIC CO.PHOTO LTH.39 1&4! P RK PLACLNY ABRAM ALEXANDER, OF PITTSBURG, ASSIGNOR TOFARRELLY ALDEN, OF

ENT Eric,

ALLEGHENY, PENNSYLVANIA.

IMPROVEMENT IN COMPOUND STEAM-ENGINES.

ossification forming part of Lrtters Patent No- 163348, dated May 18,1875; application filed January 7, 1875.

To all whom it may concern Be it known that I, ABRAM ALEXANDER, ofPittsburg, in the county of Allegheny and State of Pennsylvania, haveinvented a new and useful Improvement inOompound Steam- Engines; and Ido hereby declare the following to be a full, clear, and exactdescription thereof, reference being had to the accompanying drawingforming a part of this specitica tion, in which Figure 1 is a side viewof my improved steam-engine, and Fig. 2 is a vertical longitudinalsection of the same.

My invention relates to that class of steamengines in which, by thearrangement and op eration of suitable valves and ports, a portion ofthe exhaust steam is admitted from the front side of the piston to itsrear side, for the purpose of balancing the piston-that is, ofequalizing the steanrpressure on both sides of the piston--so that onits return stroke it is not compelled to act upon and overcome thepressure of the exhaust steam, while the remainder of the exhaust steamis at the same time admitted from the first cylinder into a secondcylinder, called a vacuum-cylinder, arranged at the end of the firstcylinder, in the same axial line therewith, and provided with a piston,which is a continuation of the piston of the first cylinder, where itoperates upon the piston therein, and drives it back. In this movementno resistance is encountered in the first cylinder, because the pistonis perfectly balanced therein, while no resistance is encountered by thepiston in the second cylinder. Then, the piston of the first cylinderbeing perfectly balanced, and there being no resistance to the movementof the piston in the second cylinder, the exhaust steam taken from thefirst cylinder, operating in the second cylinder, causes the reversestroke of the piston in the first cylinder. The result of this is a verygreat gain of power. The vacuum-cylinder is made of greater diameterthan, the first cylinder, so that, when the exhaust steam is admittedtherein, it at first operates against the piston at a pressure abovethat of the atmosphere; but this pressure is gradually reduced by thedilation of the steam as the piston recedes, until, at the end of thestroke, it is reduced to the pressure of the atmosphere.

My invention consists in the arrangement of a steam-cylinder at each endof the auxiliary cylinder, communicating therewith by means of suitablevalves and ports. The steam-cylinders operate alternately, their pistonsare balanced 011 their return strokes by the free circulation of theexhaust steam around them, and a continuous steady gain of power isefi'ected by the operation of the pis' ton of the auxiliary cylinder bythe exhaust steam admitted alternately to opposite ends from thesteamcylinders.

By my improvement I gain all the advantages of a low-pressure engine,while I dispense with the expense of a condenser.

To enable others skilled in the art to make and use my invention, I willdescribe its con struction and mode of operation.

I arrange in the same axial line a large vacuum or exhaust cylinder, 1),and two steamoylinders, a and c, and provide each with pistons b, a and0 having a stem, 61, common to all. 1 also make two valve-boxes, fand g,in which are the steamsupply valves, and the valves between thecylinders a and c and the cylinder 1). The piston cl operates the wheelh by means of the pitma-n h, and the eccentric z is connected withandoperates the pivoted arm is by means of the yoke l and rod 5. Attachedto one end of the arm 70 is a rod, m, which operates the valves in theboxes f and g, and to the other end a rod, a, which operates theescapevalves a, n a and n. In the valvebox f is a slidevalve, 1", whichoperates across the steam-ports. In this valve is a steamport, 1, and anexhaust-steam port, 2. The port 1 opens directly into the passage 3, and

the port 2 opens into the passage 4 at one end,

and at the other into the passages 3 and 5, which latter leads to theexhaust-cylinder b. In the valve-box g there is a similar slidevalve,1*, having a series of similar ports and passages, the steam-supply portbeing marked 6, the exhaust-steam port 7, the passage from the port 6 tothe cylinder 0, 8, the passage from the port 7 t0 the cylinder 0, 9, andthe passage from the port 7 to the cylinder 12, 1.0. The cylinder a isprovided with an escape-port, 11, the cylinder 12 with two escape-ports,12 and 13, and the cylinder 0 with an escape-port, 14.

The operation of this engine is as follows: Beginning with the cylindera, steam is admitted through the port 1, and passes through the passage3 into the cylinder a where, operating between the cylinder-head a andthe piston 0 it forces the piston a back to the opposite cylinder-head00 At this point the valve 1', operating by means of the arm 70 and rodm, closes the port 1, while it brings the port 2 across and inconnection with the passages 3, 4, and 5. Then a portion of the exhauststeam from the cylinder at rushes through the port 2 into the passage 4,and thence into the cylinder at behind the piston to. This brings thepressure of the exhaust steam on both sides of the piston and balancesit, so that on its reverse movement it will encounter no resistance froman unequal pressure on its front side. The remainder of the exhauststeam passes through the port 2 into the passage 5, and thence into thecylinder 1) at the rear side of the piston 11. At this instant thereverse stroke of the piston takes place, being caused by the operationof the piston in the cylinder 0. The operation in this cylinder is thesame as that just described.

While the piston-stem is moving in a direction the reverse of that justdescribed, the exhaust steam from the cylinder on, entering the cylinderb in the manner just described, operates against the piston b, so as toforce it onward to the other end of the cylinder I). When the exhauststeam enters the cylinder 1) the pressure is very much greater than thepressure ot' the atmosphere; but as the piston advances the pressure isgradually reduced by the dilation of the steam until the piston reachesthe farthest limit of its stroke, at which point, the size of thecylinder being regulated in reference to the amount of exhaust steamadmitted therein, the pressure has been reduced until it equals thepressure of the external atmosphere. Now, then, taking the cylinder 0,which is situated at the opposite end of the cylinder b, the steam is admitted through the port 6 and the passage 8 into the cylinder 0, andoperates against the piston a, forcing it onward to the cylinderhead 0at the opposite end of the cylinder. Then, by the movement of the valve1", the steam-supply is cut olf, and the port 7 is brought in connectionwith the passages 8, 9, and 10. Then a portion of the exhaust steam fromthe cylinder 0 passes through the port 7 and the passage 9 to the rearside of the piston c and balances it in the manner described inreference to the piston 0. The remainder of the exhaust steam from thecylinder 0, passing through the port 7 and passage 10, enters thecylinder 1), where it operates against the piston b, to aid in thereverse movement of the piston, in the manner before described. Whilethe piston-stem d, which carries all the pistons, is being moved forwardin either of the cylinders a or c, the discharge-port in connec:

tion with such cylinder is opened, to permit the escape of the exhauststeam which had been admitted to the rear side of the piston, while thedischarge-port of the opposite cylinder is closed, to prevent the escapeof the exhaust steam as it enters back of the piston. Also, thedischarge-ports on the opposite sides of the piston b in the cylinder 1)are alternately opened and closed, for the purpose of preventing orpermitting the escape of the exhaust steam from the cylinder 1).

Thus it will be seen that I make use of a portion of the exhaust steamfrom the cylinders, for the purpose of balancing the pistons in the endcylinders a and 0, while the remainder of the exhaust steam is admittedto the cylinder b, and utilized therein, for the purpose of aiding inthe reverse stroke of the piston. This gain is constant, because, whenthe live steam is operating against the piston in one of the cylinders aor c, the exhaust steam from the other cylinder is operating in the samedirection against the piston b, While at the same time there is noresistance of the exhaust steam in the opposite cylinder at or c.

The size of the cylinder 11 should be regulated by the amount of theexhaust steam admitted from the cylinder at or 0, so that when thepiston b has reached the end of its stroke the steam which is admittedtherein shall have been dilated or expanded until its pressure has beenreduced to that of the atmosphere. If the size of the cylinder 1) isless than this, and does not afford sufficient space for the expansionof the steam to this extent, there is a loss of power equal to thedifference between the pressure in the cylinder b and the pressure ofthe atmosphere.

What I claim as my invention, and desire to secure by Letters Patent, is

The combination of the two steam-cylinders a and c with an auxiliarycylinder, 11, each supplied with valves, ports, and pistons, having acommon stem, d, the two steam-cylinders operating alternately, andalternately admittin g their exhaust steam into the auxiliary cylinder1), to operate the piston therein, while their own pistons are balancedby the free circulation of the exhaust steam around them, substantiallyas described.

In testimony whereof I, the said ABRAM ALEXANDER, have hereunto set myhand.

ABRAM ALEXANDER. Witnesses:

T. B. KERR, JAMES I. KAY.

